Refrigeration



March 9, 1943. E. s. LYNGER REFRIGERATI 0N Filed Nov. 15, 1959 10; ATTORNEY.

Patented Mar. 9, 1943 UNITED STATES PATENT OFFICER REFRIGERATION Erik Sigfrid Lynger, Stockholm, Sweden, assignor, by mesne assignments, to Serve], Inc., New York, N. Y., a corporation of Delaware I Application November 15, 1939, Serial No. 304,507

Claims. (Cl. 62- --118) This invention relates to refrigeration, and more particularlyto'refrigeration apparatus or systems of the non-continuous or intermittent or periodic type.

The purpose of this invention is to improve the operation of systems of this type whereby the system circuit connections whereby a refrigerant evaporation period will start at the conclusion of a refrigerant expulsion period only when a certain operating condition is satisfied. In the embodiment of the invention disclosed, a heat operated device is provided which permits refrigerant evaporation to take place when heat is supplied to a part of the system other thanthe usual heat receiving part. The particular type of intermittent system provided may be operated alone, and, in addition, is particularly suited for operation in combination with a heat operated refrigerating system of a continuous type in which a moreor less steady refrigerating effect may be produced.

The heat'receiving parts of the continuous system,

and intermittent system may be arranged for heating by a common source of heat, and the,

intermittent refrigerating system may-be so constructed and arranged that the evaporation periods of v the intermittent system can take place even when the heat receiving parts of both systems are supplied with heat by the common heat source, whereby shutting off of the heat supply to the continuous system is avoided when additional refrigeration is desired from the intermittent system. With this arrangement, the intermittent system is available to produce intense refrigeration for comparatively short periods of time when such refrigeration is desired, that is, the continuous system may be arranged to carry the normal refrigerating load with the intermittent system taking care of the peak loads.

The invention, together with the above and other objects and advantages thereof, will be more fully understood upon reference :to the following description and the accompanying drawthe invention shown in connection with a continuous refrigerating system, parts of both systems being shown in section to illustrate the invention more clearly; and

Fig. 2 is a sectional view, taken on line 2-2 of by Fig. l, .to illustrate more clearly the evaporator of the intermittent system.

In Fig.1 the improved intermittent refrigerating system has been shown in connection with. a

continuous refrigerating system of a uniform pressure absorption type containing an inert gas or auxiliary agent. A system of this type includes a generator II), a. condenser IS, an evaporator l8,

and an absorber 22 which are inter-connected in solution of refrigerant in absorption liquid,,such

I as'ammonia in water,- and an inert gas or auxiliary agent, such as hydrogen.

The generator l0 includes an outer shell ll within which extends a flue l2 arranged to be heated in any suitable manner, as by a gas burner l3. A conduit l4 extends upwardly from the upper end of generator l0 and is provided with heat radiating fins l5 to form an air-cooled rectifier. The upper end of the conduit [4 is connected to the condenser [6 which is providedwith cooling fins for air cooling.

The lower end of condenser I6 is connected by a conduit I! to the evaporator I 8 which may be-of any wellz known, type. The evaporator I8 is here shown as a hollow vessel which is provided with liquid distributing trays, and the conduit l1 terminates in the upper part of the vessel.

A conduit l9 connects the lower end of evaporator 18 with one'passage of a gas heat exchanger 29. The other end of this passage is connected by a conduit 2 I with the lower part of the absorber 22. A conduit 23 connects the upper part of the absorber with one end of a second passage of heat exchanger 20, and a conduit 24 connects the opposite end of this passage with the upper part of the evaporator I8. A drain conduit 25 connects the second-mentioned passage of the gas heat exchanger with the lower part of the absorber 22, and a vapor vent 26 connects the condenser IS with the first-mentioned space of the heatexchanger 20.

A conduit 21 extends downwardly from the lower part of the absorber 22 to the inner conduit of a liquid heat' exchanger'28. The opposite end of'this conduit is connected to a pipe 29 which is.

wound in the form of a coil 30 around and in good heat exchange relation with the lower end of flue l2 and'thence extends upwardly and communicateswith the upper'part of generator I ll. Apipe 3| connects the lower part of the generator with an end of the outer conduit. of the liquid heat exchanger 28, and a conduit 32 connects the opposite end of this conduitwith the upper part of absorber 22. The absorber 22 may be cooled condenser l6 in which it is liquefied. The liquid formed in the condenser l6 fiows through conduit II to the upper part of evaporator l8. In the evaporator |8 the liquid evaporates and difiuses into an inert gas, such as hydrogen, which enters through the conduit 24, with consequent absorpin any suitable manner well known in the art, as

tion of heat from evaporator l8 and its surroundings, thereby producing a refrigerating effect. The rich gas inixture'of refrigerant and inert gas formed in the evaporator I8 flows therefrom. through the conduit l9, the heat exchanger 20, and the conduit 2| into the lower part of absorber 22.

In the absorber the rich gas mixture flows counter-current to weak absorption liquid which enters through conduit 32. The absorption liquid absorbs refrigerant from the inert gas, and inert gas weak in refrigerant flows from the absorber 22 and returns to the evaporator 3 through the conduit 23, heat exchanger 20, and conduit 24.

The enriched absorption liquid flows from the absorber 22 through the conduit 21, liquid heat exchanger 28 and conduit 29 to the coil 36. Due to heating by burner l3, liquid is raisedin coil 30 and-the vertically extending conduit connected thereto into the upper part of generator III by thermosiphon action. The-weak absorption liquid flows. from the lower part ,of generator through conduit 3|, liquid heat exchanger '28,-

and conduit 32 to the upper part of absorber 22.

' Since liquid'is introduced into the generator III.

at a point above the level at which conduit 32 discharges into the absorber 22, liquid will flow from the generator to the absorber by gravity.

In accordance with this invention, a continuous heat operated refrigerating system of the above type may be combined with an intermittent absorption refrigerating system which is particua of cross leg 50 and the upper part of vertical leg 46. A conduit 53 connects the part 50b of cross leg 50 and the upper part of vertical leg 41 in the adjacent section of the evaporator unit. All of the evaporator sections are connected together in the manner just described. In addition, vapor conduits 54 connect together the upper cross legs 49 of the several evaporator sections.

- A conduit 55 is connected to the lower cross leg 50 of the last evaporator section and extends upwardly to communicate with the upper part of a vessel 56. A conduit 51 is connected to the upper horizontal leg 49 of the last unit and extends first downwardly and then upwardly to provide a liquid trap having legs 58 and 59. The leg 59 is connected to' a. conduit 60, which in turn is connected to the upper part of an absorber 6|. A conduit 62 is connected to the lower part of the absorber 6| and the vertically extending portion thereof is connected to conduit 51 at a region between the evaporator 46 and'the leg 58 of the liquid trap. A. conduit 63 extends downwardly from vessel 56 and thence upwardly and is connected to conduit 62 at a point somewhat above the level at which conduit 55 is connected to vessel .56.

A conduit 64 extends from the bottom of absorber 6| and is connected to the lower end of a coil 65 which is arranged to be heated in any suitable manner, as by an electric heating element 66, for example. .A conduit 61- extends upwardly from the coil 65 and terminates within a vessel 68. A conduit 69 connects the lower part of vessel 68 and an intermediate point of leg 59. A

conduit 10 is connected to the upper part of vessel 6B and to an ejector 11. A conduit connects conduit 10 and the upper part of vessel 56.

A conduit 12 at its upper end extends into absorber vessel 6| andat its lower end is connected to the inner conduit of a liquid heat e'xchanger I3. The other end of this inner con- ,duit is connected to the lower end of the generator coil 40. The lower end of standpipe 4,2

is connected to an outer conduit of the heat exchanger 13, and a conduit 14 connects the other end of the outer-conduit to the upper part of absorber 6|. The ejector I1 is connected in the larly adapted for such combination and also em- 1 bodies improvements which make for better operation when employed alone. The intermittent system includes a generator 40 in the form of a coil wound around a portion of flue |2 within generator In of the continuous refrigerating system. A conduit 4| connects the upper endof generator 40 with a standpipe 42. The upper .part of standpipe 42 is in heat transfer relation with fins l5 to provide an air-cooled rectifier for the intermittent system. The standpipe 42 is connected at its upper end to condenser 43 having heat transfer fins to provide for air cooling. A conduit 44 is connected to'the opposite end of the condenser 43 and extends downwardly and then upwardly in the form of a loop to communicate with the upper part of one section 45 or an evaporator 46.

As shown most clearly in Fig. 2,'each section of the evaporator 46 includes a. vessel having ver- 'tical legs 41 and 48, an upper'cross leg 49, and

a lower cross leg 5|]. ,A partition 5| divides the lower cross leginto two parts We and 50b. The

conduit" is connected to the upper part or vertical leg 41 and aconduit 52 connects the part conduit 12. A float 15 is provided within absorber 6| and is dimensioned so as to substantially cover the entire surface of the liquid contained therein. The upper end of conduit 12 within absorber 6| is disposed at a level slightly below the upper end of conduit 61 in vessel 68 andapproximately at the same level as the lower ends of legs 58 and 59. The conduit 69 is connected to the leg 59 at a point somewhat above this level. A conduit 16 connects the upper part of standpipe 42 and the leg 59.

The above described continuous system may be arranged to produce refrigeration at a substantially constant rate. This rate can of course be varied by changing the quantity of heat supplied to generator "I by the burner l3. However, in order to be able to produce a much greater refrigerating effect for short periods of time, the intermittent system is provided, the operation of which will now be described.

The absorber 6| of the intermittent system contains a solution of refrigerant in an absorb- This solution is also present in generator coil 40, and, due to the application of heat to this coil from the flue |2 during the normal operation of the continuous system, refrigerant isex- "absorber 6|. denser 43 and flows through conduit to the pressure exists in bothof these vessels.

conduit 4| and the upper part of standpipe 42 into condenser 43. The absorption liquid is' raised in the conduit 4| by thermosiphon action and flows downwardly throughthe standpipe 42,

liquid heatexchanger I3 and conduit 14 to the The refrigerant'is liquefied in confirst section 45 of the evaporator 46. The liquid flows into leg 41 and the part 56a. of cross leg 56 which is connected thereto. The liquid also flows into conduit 52, and, as soon as leg 41 is filled up to the level indicated in Fig. 2, liquid 'starts toflow into leg 46. As soon as this leg is filled to the level indicated'in Fig. 2, the liquid flows through conduit 53 to the next section of of the sections are filled with liquid refrigerant.

During this time, legs 58 and 59 of the liquid trap have been filledwith liquid which stands at the same level as the liquid in absorber 6| since leg 59 is in communication with the absorber throughconduit 64, coil 65, conduit 61,

vessel 68 and conduit 69. By the time the evaporator 46 has been filled with liquid refrigerant, the level of the liquid in absorber 6| has dropped to the upper end of conduit 12, due tothe ex-- 'pulsion of refrigerant from the .absorbent, and

hence nomore liquid is supplied through conduit '12 to generator 40 and the expulsion of refrigerant from absorbent ceases, thereby terminating" a vapor expulsion period, although heat conorator to increase.

, '3 around the edges of thefloat, whereby the pres,- sure in the absorber is-reduced, and the tendency of the liquid refrigerant in evaporator 46 to boil or evaporate causes the pressure in the evapcannot now be equalized through legs 58 and 56 since the liquid columns are formed therein, and hence the pressure difference existing between evaporator 46 and absorber causes the liquid in conduit 62 to bepressed downwardly and into the absorber 6|. When the liquid column in conduit 62 is lowered sufficiently, refrigerant vapor passes into the absorber through this conduit from-the evaporator 46 and the absorption liquid absorbs the refrigerant vapor. This absorption of the refrigerant vapor reduces the pressure in the intermttent system, thus increasing-the rate at which refrigerant evaporates in the evaporator 46. Due to the large quantity of liquid refrigerant stored in the evaporator, a very great refrigerating efiect can be rapidly produced when a refrigerant evaporation period is initiated.

The absorption of refrigerant vapor by the solution in absorber 6| causes the level of the liquid therein to rise above, the upper end of conduit 12. By providing the ejector 11 enriched absorption liquid isprevented from flowing from absorber 6| to generator 40,;during the period of refrigerant evaporation. If enriched absorption liquid were permitted to flow into generator 46 from absorber 6| through conduit 12 7 and liquid heat exchanger 13, the pressure in the tinues to be supplied to. coil 40. When circulation of absorbent in the generator 46 ceases, the

supply of hot weak solution to the absorber 6| ,through the conduit 14 also ceases and the abwhereby the liquid in the, legs 58 and 59 of the liquid trap is forced upwardly through leg 59 and into the absorber. This produces an unobstructed connection between the vapor space at i the top of the evaporator 46 and the vapor space at the top of the absorber 6|, whereby the same it is impossible for refrigerant vapor to force the liquid downwardly in conduit 62 and refrigerant 1 vapor cannot enter the absorber through this conduit. Since the float -l5 covers substantially all of the liquid surface in absorber 6|, prac.-'

ti'caly-no absorption will-take place and the intermittent system will be'inactive at the conclusion of'a refrigerant expulsion period.

When it; is desired to produce added refrigeration in addition to that produced by-evaporator i|8 of the continuous system, an absorption period of the intermittent system is initiatedby heating the coil 65 by the heating element '66. This coil is filledyvith liquid and heating thereof the trap with liquid and establishing liquid'golumns in legs 58 and-59 and conduit 16, thereby blocking off the freecommunicationbetween the 'vapor spaces of evaporator 46 and absorber, 6|.

intermittent system would rise and prevent evaporation of liquid in the evaporator 46. As shown,

-. however, vapor in the upper part of vessel 66 Hence flows through conduit [0 to ejector 11 and liqquid in absorber 6| is prevented from flowing through conduit 12 by thermosiphon action. While heating element 66 is heating coil 65,

therefore, a vapor lock is formed in conduit 12 by ejector 11 to prevent absorptionliquid reaching generator 46 from absorber 6| during a refrigerant evaporation period.

When the need for additional refrigeration by. the intermittent system no longer exists, heating of coil is stopped. With heat no longer, supplied to coil 65 no liquid and vapor flow into vessel 68 by vapor liquid lift action and the liquid in legs 56 and 59, which has been maintained by the supply of liquid, blows through and free communication between vapor spaces of the evaporator 46 and absorber 6| is established. Refrigerant vapor now cannot enter the absorber 6| through conduit 62 and absorption ceases, W

terminating the refrigerant evaporation period.

The vessel- 56 and the conduits associated therewith are provided to remove absorption liquid which may 'find its way into the. evaporator '46, particularly di'i ring shipment of the apparatus when it may be turned upside down. The

, amount of liquid charged into the intermittent j system is so chosen with respect 'to the volumes The shortest liquid column is. formedin leg 56 'and liquid flows therefrom through conduit 60 into absorber 6|. A small amount ofabsorption takes place at the liquid surface in absorber 6| of the various vessels and conduits that, if the evaporator 46 and vessel 56 are completely filled with absorption liquid, the,level in absorber 6| is at the upper end of conduit 12. Under these conditions, when heat is applied to the coil65,

the pressure in vessel 68- canbe increased; This pressure increase "in vessel 68 ,is transmittedv 'through'conduit II to theyessel 56 whereit acts upon the absorption liquid contained therein so as to press this liquidthrough U-shaped con-,

duit 63 into the conduit 62 from whence it may flow by gravity into absorber 6|, thus raising the This difference in pressure level of the liquid therein sufliciently for flow to take place into the upper end of conduit 12.

Liquid will therefore be supplied to coil 40 and refrigerant vapor condensed in the condenser 43 from which liquid refrigerant flows through conduit 44 to the first section 45 of the evaporator.

The introductionof this liquid refrigerant into the evaporator 46 displaces an equal volume of absorption liquid from the evaporator through conduit 55 to vessel It, where it is returned in the manner just described to the absorber. During each heating or vapor expulsion period of the intermittent system, a certain amount of absorption liquidflwill in this manner be displaced from the evaporator 46 until finally it is all removed.

It will now be understoodtliat with the improved circuit arrangement provided in the in-.

\ termittent system, the production of refrigeration at the conclusion of a vapor expulsion period can be effectively controlled. vWhen the need for more-refrigeration than that produced by evaporator l8 of the continuous system exists, the coil 65 may be heated to initiate a period ofrefrigerant evaporation. The heating of coil- 65 may be continued until the evaporator 48 is depleted of liquid, thereby terminating the refrigerant. evaporation period;-' or coil 65 may intermittently be heated to produce comparatively short periods of intense refrigeration to supplement the refrigeration produced by the continuous system.

If desired, the ejector 71 may be omitted and the lower end of conduit connected to the In such case the burner I3 must be shut ofl when heating element lower end of the absorber SI.

66 is energized, since liquid can then fiow from absorber 6| into generator 40 when the liquid levelrises with absorption of refrigerant vapor.

the generator 40 are preferably so tied together that' the transfer of heat from generator 40 to coil 40 does not appreciably effect the operation of the continuous, system. The transfer of heat 1 to coil 40 may beflmade relatively small, so that.

by the periods of refrigerant evaporation can take place even when said source of heat is supplying heat to said first system.

2. Refrigeration apparatus comprising a system having alternate periods of expulsion of refrigerant from liquid absorbent and evaporation of refrigerant, said system including an evaporator and an absorber and inter-connecting conduit means therebetween' providing a first connection between the vapor space of said absorber and the vapor space of said generator and a second connection between the vapor space of said evaporator and the absorber below the liquid level therein, said first connection including a trap normally clear of liquid at'the conclusion of a refrigerant expulsion period whereby the vapor spaces of said absorbent and said evaporator have communication and are at substantially the same pressure whereby evaporation of refrigerant is prevented, and means to cause blocking liquid to fiow' in said trap and also effect a'f reduction in absorber pressure whereby the vaporspaces of said absorber and said evaporator are no longer in communication through said first connection and refrigerant vapor flows from said evaporator through saidsecond connection to said absorber to initiate a refrigerant. evaporation period.

3. Refrigeration apparatus as set forth in claim 2 in which said refrigerant evaporation period stops when said means to cause blocking liquid to fiow in said trap is rendered inoperative and said trap is again free of liquid.

4. Refrigeration apparatus including a first heat operated refrigeration system having a heat receiving part and a second heat operated refrigeration system having a heat receivin part and operating with alternate periods 'of exp lsion of refrigerant from absorbent and evaporation of refrigerant, the heat receiving parts of said systems being in heat exchange relation, means other than said source of heat for controlling the periods of refrigerant evaporation of said second system, and means to block off flow of absorption liquid in said second system whereby the periods of refrigerant evaporation can take place even when said source of heat is supplying heat to said heat receiving parts.

the heating or vapor expulsionper-iod of the inter'rnittent system may be as long as 8 to 10 hours, for example. This can readily be effected by properly dimensioning the generator HI and coil 40. With this arrangement only a small amount of heat is transferred per unit of time from generator Hi to absorber 6|.

Although a single embodiment of the invention has been shown and described, such variations and modifications are contemplated as fall within the true spirit and scope of the invention, as

pointed out in the following claims.

What is claimed is:

.- 1. Refrigeration apparatusincluding a first heat operated refrigerating system and a second heat operated refrigerating system having alternate periods of expulsion of refrigerant from absorbent and evaporation of refrigerant, a common. source of heat for said systems, means other. than said source of heat for controlling the periods of refrigerant evaporation of said second system,

and means embodied in said secondsystem where-- 5. An intermittent absorption refrigerating system including an absorber, anevaporator, a conduit connecting the vapor space of said evapo- 1 rator and said absorber below the liquid level therein, a conduit connecting the vapor space of.

said, evaporator and the vapor space of said 'absorber, the last mentioned conduit being arranged to have a trap, and means for introducing liquid into and withdrawing liquid from said last mentioned conduit to seal and unseal said trap.

. 6. An intermittent absorption refrigerating system including an absorber, an evaporator, a conduit connecting the vapor space of said evaporator and said absorberbelow the liquid level therein, a conduit connecting thevapor space of said evaporator and the vapor space of said absorber, the last mentioned conduit being arranged to have a trap, and means for. withdrawing liquid from said absorber andintroducing it into said last mentioned conduit to seal sai d trap and withgrawing liquid frorn'said conduit to unseal said ran 7. An intermittentabsorption refrigerating system including an absorber; an evaporator, a conduit connecting the vapor space of said evaporator and saidabsorber below the liquid level therein, a conduit connecting the vapor space of said evaporator and ,the vapor space of said abduits interconnecting the aforementioned parts an intermittent absorption refrigerating system sorber, the last-mentioned conduit having a pair of vertically extending legs joined at their lower ends to provide a trap, the vertical extent of said legs being greater than the liquid headin the first-mentioned conduit, and means for introducing liquid into and withdrawing liquid from said legs to seal and unseal said trap.

8. An intermittent absorption refrigerating system including an absorber, an evaporator, a conduit connecting the vapor space of said evaporator and said absorber below the liquid level therein, a conduit connecting the vapor space of said evaporator and the vapor space of said absorber, the last-mentioned conduit having a pair of vertically extending legs joined at their lower ends to provide, a trap, a vessel, a conduit connectingthe lower part of said vessel with said legs, and means for supplying liquid under pressure to said vessel to establish a liquid seal in said trap.

9. An intermittent absorption refrigerating system including an absorber, an evaporator, a conduit connecting the'vapor space of said evaporator and said absorber below the liquid level therein, a conduit connecting'the space of said evaporator and the vapor space of said absorber, the last-mentioned conduit having a pair of vertically extending legs joined at their lower ends to provide a trap, a vessel, a conduit connecting the lower part of said vessel with said legs, and a thermosiphon'pump for withdrawing liquid from said absorber and supplying it to said vessel under excess pressure for establishing a liquid seal in said trap.

10. Refrigeration apparatus including a continuous refrigerating system having a heat receiving part and anevaporator, a source of heat for said heat receiving part, an intermittent absorption refrigerating system having a second said second evaporator and the vapor space of said absorber, the last-mentioned conduit being ducing liquid into said last-mentioned conduit to seal said trap to initiate a. refrigerant evaporation period of said intermittent system.

11. Refrigerating apparatus including an absorption refrigerating system having a generator, condenser, evaporator, absorber and con-' having a generator, condenser, evaporator, absorber and conduits interconnecting the aforementioned parts, a heater for heating both of,

said generators whereby a refrigerant expulsion period of said intermittent system takes place during operation of said first-mentioned system, and means independent of said heater for-eifect-- ing a refrigerant evaporation period of said intermittent system.

12. Refrigeration apparatus includingan aborption refrigerating system having a generator,

condenser, evaporator, absorber and conduits interconnecting .the aforementioned parts, an intermittent absorption refrigerating system having a generator, condenser, evaporator, absorber 4 and conduits interconnecting the aforementioned by a refrigerant expulsion period of said intermittent system takes place during operation of said first-mentioned system, and means for effecting a refrigerant evaporation period of said intermittent system during an inactive period of said first-mentioned system to produce in refrigerating capacity.

13. Refrigerating apparatus including a first absorption refrigerating system having a generan increase ator, condenser, evaporator, absorber and conduits interconnecting the a'forementioned'parts, an intermittent absorption refrigerating system having a generator, condenser, evaporator, ab-

sorber and conduits interconnecting the aforementioned parts, common means for heating both of said generators whereby a refrigerant expulsion period of said intermittent apparatus takes place during operation of said first-mentioned arranged to have a trap, and means for introsystem, one of said conduits through which liquid flows from said absorber to said generator of said intermittent system communicating with said absorber so as to cut off flow to said generator when: the level in the absorber drops below the upper end of said conduit to terminate a vapor expulsion period of said intermittent system, and means to control the refrigerant evaporation period of said intermittent system.

I 14. Refrigeration apparatus including a heat operated continuousrefrigerating system and an absorption refrigerating system of an intermittent type, means for supplying heat to the firstmentioned system at a, substantially constant rate in order to produce refrigeration at a sum stantially constant rate and simultaneously suply n heat to said intermittent system to effect 7 refrigerant expulsion period therein, and means for initiating a refrigerant evaporation period 1 in 'said intermittent system upon an demand for refrigeration.

15. An absorption refrigerating system of an intermittent type having a generator, a condenser, an absorber, an evaporator and interconnecting conduits including conduits connecting the vapor space of said evaporator to both the liquid and vapor spaces of said absorber, means for heating said generator to expel refrigerant vapor from absorbent, condense the refrigerant in said condensenand flow the liquid refrigerant to said evaporator, and means operable upon a demand for refrigeration for shutting off flow of absorbent to said generator and segregating the increase in vapor space of said evaporator and the vaporspace of said absorber to cause flow of refrigerant vapor from said evaporator into contact with absorbent in said absorber.

- ERIK SIGFRID LYNGER. 

